During the shearing season, the shearing shed is a busy place. Frustration levels can easily run high when things don’t go according to plan. A farmer is therefore obliged to design the shearing complex with every possible factor in mind.
We thank the ARC – Agricultural Engineering in South Africa for making their manual on sheep production and facilities available to the readers of ProAgri Zambia.
As discussed previously, the layout of different handling facilities varies a lot. In general, distinction can be made between rectangular and non-rectangular facilities. In this article, a number of typical existing layouts are discussed according to the aforementioned articles.
-The layout extends over an area of ± 1 350 m² and can be used for 1 500 sheep.
-The double working alley increases the flow tempo and the sheep can be handled successfully by one or more handlers simultaneously.
-The position of the dip is favourable if the dipping process is part of the handling process. If other handling actions take place and the sheep do not move through the dip, the movement of the sheep is hampered by the sharp turn the sheep have to make to the working alley.
-The capacity of the gathering pen before the double working alley is greater than the capacity of one of the alleys, but too small to fill both alleys. This surface can be made smaller or enlarged to better adjust to the working alley capacity.
-The holding pens before the crush or working alleys can be elongated slightly and narrowed to increase effectiveness.
The benefits of non-rectangular layouts above rectangular layouts include:
-Movement of sheep is better because the same route is always followed, and corners are limited to the minimum.
-It is cheaper because the same pre-holding pen can be used for the crush, working alley, dip and shearing pen.
-Movement distances for the handler are shorter and therefore make
-Planning of this type of layout is, however, very important to ensure that the correct shape and dimensions are obtained.
Shearing sheds form an integral part of the intensive production system, especially at current wool prices. The extra income obtained from the wool is determined by efficient facilities and handling of the wool. It is therefore important that the structure be placed correctly and be functional.
Regarding the specific placing of the structure, the distance that the sheep will have to move must be considered. The facility will therefore have to be placed as close as possible to the housing and handling areas.
Most farms are already developed to some extent and existing buildings can possibly be adapted into shearing sheds, which can mean great cost savings for the farmer. It is however important that the existing buildings should be critically evaluated according to the following conditions or directives:
-Height of structure: The minimum height of the structure must be
3 070 mm.
If the structure is lower than this, sunken pits will have to be used.
Sunken pits or sunken sheep exits are usually expensive and can be the source of many problems.
-Length of structure: A minimum length of 12 000 mm is required. This length does not include the space needed to provide sufficient storage space for wool bales. The ideal would be that the structure should be long enough to provide storage space for the wool as well as eliminating unnecessary shifting.
-The width of the structure: The width of the structure depends on the number of shearing points and a distance of 2 320 mm plus 800 mm of free space is required per shearing point.
-Lighting: Sufficient light must be available inside the building for the work to run smoothly. Artificial lighting, additional windows or transparent roof sheets must be considered if lighting is insufficient. Recommended minimum lighting values are 400 lux on the shearing floor, 600 lux at wool handling, and 200 lux for the wool press area. In order to calculate the Watts needed and globe specifications, the following thumb rule can be used: 10 lux = one Watt per 0,37 m² floor surface if the light source is two metres away from the object.
-Ventilation: The activity levels in the shearing shed are high and good ventilation is necessary to create a comfortable work environment. The required ventilation will be determined by climatic conditions. Additional windows, wall and roof openings, sliding doors or fans can be installed to provide the necessary airflow.
-Age of building: A very old building will necessitate more frequent maintenance and can become expensive in the long run. Some old buildings cannot withstand alterations easily, because of building material and construction methods.
-Position of building: The building must be located to easily integrate with the rest of the facilities. Potential extensions will also determine whether the old building could be used or not.
Types of shearing sheds
Three types of shearing sheds can be distinguished, namely:
-Sliding chute shearing shed
-Crush shearing shed
-Feedback alley shearing shed
Sliding chute shearing shed
Sliding chute structures are the most popular type of shearing shed and have the following advantages:
-Sheared and unsheared sheep are handled on different levels and therefore there is no crossing in the movement of sheared and unsheared sheep. The sheep flow is therefore fast and easy.
-The height difference of 800 mm between the shearing floor and the floor of the wool handling area makes the handling of the fleece easier and smaller bits are handled at a comfortable height.
The operation of this type of shearing shed is discussed according to Figure 3.
Sheep enter by way of the alley (A) through the sliding door up to the interior of the shearing shed. The sheep are now guided from the alley (B) by means of swing gates, or lift-and-swing gates in the filling pens (C). The filling pens serve as reserve storage space for the gathering pens (D) and can be considered as optional if the available funds or space does not allow it. From the filling gate, the sheep move to the gathering pen where the shearer drags the sheep through the entrance door (E) onto the shearing floor (F). The sheep is now sheared on the shearing floor and pushed towards the sliding chute (G) to the underfloor area. The sheared sheep then move through beneath the slatted floor, on which the unsheared sheep are waiting, to the outside where they are kept in collecting pens. Each shearer’s sheep is kept in a separate collecting pen to be counted later.
Crush shearing shed
This type of shearing shed was developed from a conventional sliding chute shearing shed. Instead of having a back alley, filling pens and gathering pens, this shearing shed only has a crush from where sheep are taken for shearing.
This structure has the following advantages:
The type of structure is compact and therefore requires less space and lower construction costs.
The level on which the sheep are made available to the shearer is 600 mm above the shearing floor. The height is comfortable for the handler and simplifies his task to speed up the entire process.
The profit in space means loss of space of a holding area and places a burden on the handler, because the crush must always be kept filled. This means that if any problems occur with the flow of sheep, the entire process will come to a standstill.
The operation of the crush shearing shed is discussed below in Figure 4.
Feedback alley shearing sheds
With this type of structure, sheared and unsheared sheep are handled on the same level. This means that movement of different groups of sheep will cross.
This makes sheep flow more difficult and can waste time. With feedback alley shearing sheds, a larger slatted floor area is required for the same number of shearing points as with the two previous structure types, because the sheared sheep are also kept on the floor for some time.
Feedback alley shearing sheds have the following advantages:
-Sheared sheep remain under shelter for a reasonably longer period, which is beneficial when shearing takes place during wet or cold conditions.
-The sheared sheep are visible to all the shearers and this can benefit the shearing standard.
-This type of shearing shed can be easily equipped in existing buildings, especially where height is a problem.
The operation of the feedback alley shearing shed is explained below according to Figure 5.
Sheep enter the shed by way of the walk-up alley (A), through the sliding door and move into the holding pens (B). By setting the gates at the holding pen (B) and the filling pen (D), a passage can be formed, which crosses the alley (C). Sheep move through here from the holding pen to the filling pen and then to the gathering pen (E).
As soon as the gathering pens are filled with sheep, the gates are closed and alley (C) is open again. The shearer now gets his sheep through the gate (E1) from the gathering pen (E) and shears the sheep on the shearing floor (F). The sheared sheep is then released in alley (G) where all the sheared sheep are gathered. When the alley (G) is filled with sheep, the gate (G1) is opened, and the sheared sheep then move out of the shearing shed along alley (C) and exit (H).
Next month we shall look at the different areas needed in the shearing complex. Published with acknowledgement to the ARC – Agricultural Engineering for the use of their Sheep Facilities Manual. Visit www.arc.agric.za for more information.